• Cryptographic Cards: The PCIXCC and PCICA cards
plug in the I/O cage and can be added or replaced con-
currently with system operation.
• Redundant Cage Controllers: The Power and Service
Control Network features redundant Cage Controllers for
Logic and Power control. This design enables nondis-
ruptive service to the controllers and virtually eliminates
customer scheduled outage.
• Auto-Switchover for Service Element: The z990 has two
Service Elements. In the event of failure on the Primary
SE, the switchover to the backup is handled automati-
cally. There is no need for any intervention by the cus-
tomer or Service Representative.
Concurrent Capacity Backup Downgrade (CBU Undo)
This function allows the customer to downgrade the disas-
ter backup machine to its normal conﬁ guration without
requiring the PowerOn Reset (POR).
Concurrent Memory Upgrade
This function allows adding memory concurrently, up to the
maximum amount physically installed.
Parallel Sysplex clustering was designed to bring the
power of parallel processing to business-critical zSeries
and S/390 applications. A Parallel Sysplex cluster consists
of up to 32 z/OS and/or OS/390 images coupled to one or
more Coupling Facilities (CFs or ICFs) using high-speed
specialized links for communication. The Coupling Facili-
ties, at the heart of the Parallel Sysplex cluster, enable
high speed, read/write data sharing and resource sharing
among all the z/OS and OS/390 images in a cluster. All
images are also connected to a Sysplex Timer® to address
Parallel Sysplex Resource Sharing enables multiple system
resources to be managed as a single logical resource
shared among all of the images. Some examples of
resource sharing include Automatic Tape Switching (ATS
star), GRS “star,” and Enhanced Catalog Sharing; all of
which provide simpliﬁ ed systems management, increased
performance and/or scalability. For more detail, please see
S/390 Value of Resource Sharing
white paper – GF22-5115
on the Parallel Sysplex home page at ibm.com/servers/
Parallel Sysplex Cluster Technology